Question

Vexillum is found in
(A) Rosaceae
(B) Papilionaceae
(C) Cruciferae
(D) Solanaceae

Answer 1

Hint: The larger outermost petals are called a vexillum, whereas the two laterally arranged curved petals are identified as wings. The two innermost and boat-like arranged petals are identified as keels. This type of aestivation is the characteristic feature of this family.

Complete answer:
Aestivation is referred to as the arrangement of the flower parts based on their positioning inside the bud of a flower, prior to its opening. Aestivation can be determined as the arrangement of accessory floral parts such as petals or sepals, related to each other in a flower.

Aestivation in Rosaceae- The Rosaceae or the rose family shoes valvate aestivation. In this the sepals are found in a whorl and touch each other at margins but they don’t overlap.

Aestivation in Papilionaceae- The pea family or Papilionaceae shoes vexillary aestivation. In this the corolla is arranged so that the anterior petal is innermost and the posterior petal is the largest and present at the outermost. The large petal has its two lobes fused. They have two wings and one small keel.

Aestivation in Cruciferae- The members of this cabbage or mustard family show imbricate aestivation. In this one petal or sepal is internal or is found to overlap on both the margins. The other one is external in which both its margins overlap. For the rest of the petals, one margin is overlapping.

Aestivation in Solanaceae- The members of the nightshade family shows valvate aestivation in which the sepals are united.

Thus, the correct answer is option ‘B’.

Note: The most distinct characteristic of the plants present in this family is the presence of root nodules which has the ability to fix free atmospheric nitrogen. The Rhizobium bacteria is present symbiotically in the root nodules.